2017-06-02T14:51:17ZACS PublicationsCHEMBIOPOLE 3Preparation of Substituted 2H-Pyrans via a Cascade Reaction from Methyl Coumalate and Activated Methylene NucleophilesThe reaction of methyl coumalate with a wide range of methylene active compounds, such as keto-esters or keto-sulfones and cyclic or acyclic diketones, afforded more than 30 2,3,5,6-tetrasubstituted 2H-pyrans. The reaction proceeds via a cascade reaction involving a Michael addition-6π-electrocyclic ring opening-proton transfer and 6π electrocyclization, in which a variety of functional groups were tolerated.5499-550510.1021/acs.joc.7b00761http://dx.doi.org/10.1021/acs.joc.7b00761